Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    The Social Licence to Operate and the legitimacy of resource extraction
    Meesters, M.E. ; Wostyn, Piet ; Leeuwen, J. van; Behagel, J.H. ; Turnhout, E. - \ 2021
    Current Opinion in Environmental Sustainability 49 (2021). - ISSN 1877-3435 - p. 7 - 11.
    The Social Licence to Operate (SLO) has emerged as a leading concept to assess the legitimacy of extractive operations. This article examines recent SLO literature to discuss how the SLO is conceptualized and enacted. Our discussion focuses on three main themes: (1) who are considered to be relevant stakeholders; (2) the ways in which these stakeholders are engaged; and (3) how social and environmental impacts of extractive operations are considered. Our analysis points to a tendency in literature to focus on local stakeholders and a failure to consider wider sustainability implications. On the basis of these findings we argue that the evaluation of extractive operations must be based on a comprehensive concept of legitimacy that not only seeks the approval of local stakeholders but also recognises the importance of openended political deliberation that addresses global norms of social and environmental sustainability and includes diverse values, needs and interests.
    High levels of dioxins and PCBs in meat, fat and livers of free ranging pigs, goats, sheep and cows from the island of Curaçao
    Hoogenboom, Ron L.A.P. ; Dam, Guillaume ten; Leeuwen, Stefan P.J. van; Egmond, Harry van; Nicolina, Jennyfer ; Dwarkasing, Arnold J.S. - \ 2021
    Chemosphere 263 (2021). - ISSN 0045-6535
    Dioxins - Fat - Foraging animals - Liver - Meat - PCBs

    Samples of adipose tissue, meat and livers from pigs, cows, sheep and goats from Curaçao were analysed for polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), and dioxin-like (dl-) and non-dioxin-like (ndl-) PCBs (polychlorinated biphenyls). Levels in many samples of adipose tissue were higher than the EU maximum levels (MLs) for PCDD/Fs and the sum of PCDD/Fs and dl-PCBs (sum-TEQ), indicating unusually high levels. Median sum-TEQ (Toxic Equivalents) levels for pigs, cows, sheep and goats were 0.9 (range 0.3–35), 3.0 (0.5–14), 5.7 (0.3–28) and 6.5 (0.5–134) pg TEQ g−1 fat. For most samples, the congener pattern pointed to the burning of waste as the major source, in line with the fact that most animals forage outside. MLs for ndl-PCBs were also exceeded in some of the samples, indicating that some areas are additionally contaminated with PCBs. Meat levels showed similar lipid based levels as adipose tissue, contrary to liver levels, which were much higher in most animals. Pigs showed liver sequestration at lower levels in adipose tissue than the ruminants. The relatively high levels observed in this study are likely to result in high exposure of consumers and measures were taken to reduce the contamination of areas where animals forage.

    The Potential and Limits of Environmental Disclosure Regulation: A Global Value Chain Perspective Applied to Tanker Shipping
    Poulsen, Rene Taudal ; Ponte, Stefano ; Leeuwen, J. van; Rehmatulla, Nishatabbas - \ 2020
    Global Environmental Politics 21 (2020)2. - ISSN 1526-3800 - 22 p.
    Exploring how transnational environmental governance and the operation of global value chains (GVCs) intersect is key in explaining the circumstances under which mandatory disclosure can improve the environmental footprint of business operations. We investigate how the governance dynamics of the tanker shipping value chain (a major emitter of greenhouse gases) limits the effectiveness of the European Union (EU) monitoring, reporting, and verification (MRV) regulation, which mandates the disclosure of greenhouse gas emissions for ships calling at EU ports. Although MRV seeks to help shipowners and ship managers save fuel and reduce emissions, it does not address the complexity of power relations
    along the tanker shipping value chain and currently cannot disentangle how different actors influence the design, operational, commercial, and ocean/weather factors that together determine fuel consumption. In particular, the EU MRV neglects to reflect on how oil majors exert their power and impose their commercial priorities on other actors, and thus co-determine fuel use levels. We conclude that, in its current form, the EU MRV is unlikely to lead to significant environmental upgrading in tanker shipping. More generally,
    we argue that regulators seeking to facilitate environmental upgrading need to expand their focus beyond the unwanted behaviors of producers of goods and providers of services to also address the incentive structures and demands placed on them by global buyers.
    Biomass Strategies and Sustainability Implementation Towards a Bioeconomy
    Elbersen, B.S. ; Leeuwen, M.G.A. van; Meesters, K.P.H. ; Broeze, J. ; Jongschaap, R.E.E. ; Bugter, R.J.F. ; Mostert, P.F. ; Fels, H.J. van der; Piet, G.J. ; Vries, M. de - \ 2020
    Data from: The ovipositor actuation mechanism of a parasitic wasp and its functional implications
    Meer, Noraly M.M.E. van; Cerkvenik, Uroš ; Schlepütz, Christian M. ; Leeuwen, Johan L. van; Gussekloo, Sander W.S. - \ 2020
    Wageningen University & Research
    Diachasmimorpha longicaudata - Hymenoptera - musculature - Ovipositor biomechanics - Surface reconstruction - synchrotron X-ray micro-computer-tomography
    Parasitic wasps use specialized needle-like structures­­—ovipositors—to drill in substrates to reach hidden hosts. The external ovipositor (terebra) consists of three interconnected, sliding elements (valvulae) which are moved reciprocally during insertion. This presumably reduces the required pushing force on the terebra and limits the risk of damage whilst probing. Although this is an important mechanism, it is still not completely understood how the actuation of the valvulae is achieved, and it has only been studied with the ovipositor in rest position. Additionally, very little is known about the magnitude of the forces generated during probing. We used synchrotron X-ray microtomography to reconstruct the actuation mechanism of the parasitic wasp Diachasmimorpha longicaudata (Braconidae) in four distinct phases of the probing cycle. We show that only the paired first valvulae of the terebra move independently, while the second valvula moves with the metasoma (‘abdomen’). The first valvula movements are initiated by rotation of one chitin plate (first valvifer) with respect to another such plate (second valvifer). This is achieved indirectly by muscles connecting the non-rotating second valvifer and the abdominal ninth tergite. Unlike previously reported, we found muscle fibres running inside the terebra, although their function remains unclear. The estimated maximal forces that can be exerted by the first valvulae are small (protraction 1.19 mN and retraction 0.874 mN), which reduces the risk of buckling but are sufficient for successful probing. The small net forces of the valvulae on the substrate may still lead to buckling of the terebra; we show that the sheaths surrounding the valvulae prevent this by effectively increasing the diameter and second moment of area of the terebra. Our findings improve the comprehension of hymenopteran probing mechanisms, the function of the associated muscles, and the forces and damage limiting mechanism that are involved in drilling a slender terebra into a substrate.
    Does population decline lead to a "populist voting mark-up"? A case study of the Netherlands
    Leeuwen, Eveline S. van; Halleck Vega, Solmaria ; Hogenboom, Vera - \ 2020
    Regional Science Policy and Practice (2020). - ISSN 1757-7802
    broad welfare - population decline - populist voting - the Netherlands

    The main thesis of this paper is that people in areas of (expected) population decline vote more populist to express their discontent about the current and future state of their place of residence. In many ways a “populist voting mark-up” could be expected, as declining areas often are associated with being forgotten, fomenting societal discontent and mistrust in established political parties ultimately expected to lead to more populist votes. Using the outcomes of the Dutch national elections in 2012 and 2017, we link shares of populist votes for the PVV (Party for Freedom) and SP (Socialist Party) to indicators of population decline, as well as other demographic (“compositional effects”), local and regional characteristics (“contextual effects”) to appraise what causes higher rates of votes for populist parties in regions of decline. We do not find a “populist voting mark-up” for declining regions when controlling for contextual effects. However, we do find that both the compositional and the contextual circumstances in areas of population decline are in such a way that they provoke discontent expressed in voting. We also conclude that it is very important to distinguish between different parties when their party programs are as contrasting as in the case of the PVV and the SP. Their different focus on immigration (PVV) and jobs (SP) is clearly visible in the results.

    Monitoring contaminanten in Nederlandse vis en visserijproducten
    Leeuwen, S.P.J. van - \ 2020
    Wageningen Food Safety Research - 8 p.
    From resolving land disputes to agrarian justice–dealing with the structural crisis of plantation agriculture in eastern DR Congo
    Leeuwen, Mathijs van; Mathys, Gillian ; Vries, Lotje de; Haar, Gemma van der - \ 2020
    The Journal of Peasant Studies (2020). - ISSN 0306-6150
    agrarian change - agrarian justice - DR Congo - Land disputes - mediation - peacebuilding - political economy

    Land disputes in conflict-affected settings are often considered as a security threat, to be addressed through mediation and strengthening the rule of law. This overlooks the roots of land conflicts in longer-term processes of agrarian development and worsening conditions of land and labour access. A case-study of a dispute between former plantation labourers and concession holders in eastern DR Congo shows mediation's incapacity to counter perceived structural injustices in land access and difficulties in making a living. While dispute resolution may temporarily calm down tensions, it cannot substitute for fundamental political choices vis-a-vis wider questions of agrarian development and justice.

    Report on description of baseline scenario for EU bioeconomy and of alternative scenarios for EU's bioeconomy future : D6.1
    Panoutsou, C. ; Arrekul, O. ; Christensen, T. ; Singh, A. ; Verkerk, H. ; Philippidis, G. ; Leeuwen, M.G.A. van; Sturm, V. ; M'Barek, R. ; Wesseler, J.H.H. - \ 2020
    - 49 p.
    Bioeconomy is very important forthe European transition to circular and low carbon societieshowever themultiple and interrelated economic sectors involved increase the complexity of metrics and constraint the comparability of the various options. With the new Green Deal, announced in the end of 2019 asEurope’sresponse to climate and environmental-related challenges,theneed for improved knowledge and foresight capacities to guide policy and decision makingis now more prominent than ever. One of the research topics in the BioMonitor project, isto quantify the bioeconomy’s environmental, economic, and social impacts in the EU and its Member States and perform scenario based quantitative and qualitative assessment to inform future policy making in this domain.This report presents the baseline(BioMonitor Reference Scenario-BRS)and the alternative scenarios that will be used to analyse the development of the bioeconomy in Europeand give model-based evidence on the potential impacts of policy,technological changesand consumer preferences. Scenario results will be quantified (using policy relevant bioeconomy indicators from the ones developed in WP1)in WP3 (ex-post) and WP5 (ex-ante) and will be disseminated by infographics in WP9. In this report there are two Appendixes. Appendix 1 provides an overview of the current policy landscape for EU bioeconomyby sector and value chain stage(i.e. land use & biomass production, conversion, distribution, end use).The information will be used as the basis for the work in Tasks 6.3 and 6.4 to understand which policies per value chain stage need to be included in the Biomonitor scenarioanalysis. Appendix 2 attempts totranslate the existingset of directives, standards, policies and strategies that (in)directly relate to the EU bioeconomy into ‘model’ language. To do so it outlines a non-exhaustive list of drivers that impact policy relevant modelling for the current EU policies.The deliverable will remain a working document throughout the project duration to ensure input from stakeholders and all relevant updates from WPs 1-5 and any changes or updates of relevant policyare integrated during the project.
    State building and land conflict in South Sudan
    Justin, Peter Hakin - \ 2020
    Wageningen University. Promotor(en): J.W.M. van Dijk, co-promotor(en): W. Verkoren; M. van Leeuwen. - Wageningen : Wageningen University - ISBN 9789463955959 - 182

    In recent decades, international organisations and donor governments have promoted state-building as a way to bring lasting peace to war-torn societies around the world. However, this approach has not yielded the hoped-for results. This thesis helps to understand why this is so via a case study of South Sudan, the youngest state in the world. In 2005, the Government of Sudan and the Sudan People's Liberation Army/ Movement (SPLA/M) signed the Comprehensive Peace Agreement (CPA). That agreement ended a civil war that had lasted for more than two decades, killed an estimated 2.5 million people and displaced more than half of the population of South Sudan. The CPA marked the start of a state-building project in South Sudan that aimed to contribute to peace, stability, and development and prevent the country from relapsing to violence. In 2011, South Sudan was established as an independent state. With support from international organisations and donor countries, from 2005 onwards, the South Sudanese government introduced reform programmes that focused on the promotion of institutions modelled on the European state. However, this state-building intervention became a trigger to local conflicts that escalated into widespread violence. Civil war broke out in late 2013, and the situation remains volatile.

    This thesis aims to explore how state-building interventions became a cause of local conflicts in South Sudan, and how those conflicts are connected to wider outbreaks of violence. Rather than taking the CPA as its starting point, the thesis places the latest state-building effort in a longer historical continuum of colonial and postcolonial attempts at institution building in South Sudan. The analysis focuses on the crucial issues of land reform, decentralisation and the governance of displaced people, all of which have played important and problematic roles in the development of animosities in South Sudan.

    Through a combination of literature research with intensive fieldwork in Central Equatoria State and Yei River County, this thesis arrives at the following findings. First, post-conflict settings like South Sudan are the hybrid outcome of history and local contexts, and state-building intervention that ignores this history and context can contribute to violence. Secondly, decentralising land governance in war-torn societies as a way of redressing past injustices on land can result in further tenure insecurity. Thirdly, civilians displaced by civil wars are not necessarily victims: they can become the agency of land occupation and change in land governance. The changes they introduce may persist and become institutionalised after the end of a civil war, which can prepare the ground for further conflict.  Drawing on these findings, this thesis concludes that, on the one hand, the top-down approaches to state-building interventions in post-conflict settings can cause instability, violence, displacements and human suffering. On the other hand, practical considerations at local levels can lead to the emergence of hybrid forms of governance resulting from interactions between a multiplicity of institutions and actors, and outcomes of this hybridity can be beneficial to local people.

    Ultrasterk pantser van kever ontrafeld
    Leeuwen, J.L. van - \ 2020
    Non-targeted identification of per- and polyfluoroalkyl substances at trace level in surface water using fragment ion flagging
    Hensema, Thijs J. ; Berendsen, Bjorn J.A. ; Leeuwen, Stefan P.J. van - \ 2020
    Chemosphere (2020). - ISSN 0045-6535
    Fragment ion flagging - Non-targeted screening - PFAS - Trace level

    The extent of unidentified Per- and Poly-fluoroalkyl substances (PFASs) found in environmental samples has led to the development of non-targeted screening methods. The study presented here reports the use of liquid chromatography hyphenated with high resolution mass spectrometry to detect and identify unknown and unexpected PFASs by fragment ion flagging (FIF). By exploring all ion fragmentation spectra for several characteristic fragments including CnF2n+1, CnF2n-1, CnF2n-3, CnF2n-7, CnF2n-11 and CnF2n+1O the presence of widely different PFAS species can be anticipated without the need for targeted screening methods. These fragments are then related to their precursor ion by retention time matching and subsequently identified. With this methodology 40 PFASs were (tentatively) identified in four surface water samples sampled throughout the Netherlands. To the best of the authors’ knowledge, four PFASs found through FIF are newly discovered species and have not been mentioned in any database or literature. This methodology eliminates the dependence on commonly reported full scan feature selection techniques such as mass defect filtering, homologous series detection and intensity threshold filtering, allowing the identification of PFASs at trace levels. Additionally, eight of the (tentatively) identified PFASs are not part of homologous series, stressing the shortcomings of commonly reported non-targeted PFASs screening methods and demonstrating the importance of more effective identification strategies such as FIF. Moreover, we like to emphasise that this approach is applicable to real-life environmental samples with PFASs at background concentration levels.

    Incorporating prior knowledge
    Leeuwen, Paul van; Vlek, Rutger - \ 2020
    Preprocessing, visualisation and quality of data
    Leeuwen, Paul van - \ 2020
    Design of Tree-Frog-Inspired Adhesives
    Langowski, J.K.A. ; Dodou, Dimitra ; Assenbergh, Peter van; Leeuwen, J.L. van - \ 2020
    Integrative and Comparative Biology 60 (2020)4. - ISSN 1540-7063 - p. 906 - 918.
    The adhesive toe pads of tree frogs have inspired the design of various so-called ‘smooth’ synthetic adhesives for wet environments. However, these adhesives do not reach the attachment performance of their biological models in terms of contact formation, maintenance of attachment, and detachment. In tree frogs, attachment is facilitated by an interconnected ensemble of superficial and internal morphological components, which together form a functional unit. To help bridging the gap between biological and bioinspired adhesives, in this review, we (1) provide an overview of the functional components of tree frog toe pads, (2) investigate which of these components (and attachment mechanisms implemented therein) have already been transferred into synthetic adhesives, and (3) highlight functional analogies between existing synthetic adhesives and tree frogs regarding the fundamental mechanisms of attachment. We found that most existing tree-frog-inspired adhesives mimic the micropatterned surface of the ventral epidermis of frog pads. Geometrical and material properties differ between these synthetic adhesives and their biological model, which indicates similarity in appearance rather than function. Important internal functional components such as fiber-reinforcement and muscle fibers for attachment control have not been considered in the design of tree-frog-inspired adhesives. Experimental work on tree-frog-inspired adhesives suggests that the micropatterning of adhesives with low-aspect-ratio pillars enables crack arresting and the drainage of interstitial liquids, which both facilitate the generation of van der Waals forces. Our analysis of experimental work on tree-frog-inspired adhesives indicates that interstitial liquids such as the mucus secreted by tree frogs play a role in detachment. Based on these findings, we provide suggestions for the future design of biomimetic adhesives. Specifically, we propose to implement internal fiber-reinforcements inspired by the fibrous structures in frog pads to create mechanically reinforced soft adhesives for high-load applications. Contractile components may stimulate the design of actuated synthetic adhesives with fine-tunable control of attachment strength. An integrative approach is needed for the design of tree-frog-inspired adhesives that are functionally analogous with their biological paradigm.
    Defusing Land Disputes? The Politics of Land Certification and Dispute Resolution in Burundi
    Tchatchoua-Djomo, Rosine ; Leeuwen, Mathijs van; Haar, Gemma van der - \ 2020
    Development and Change 51 (2020)6. - ISSN 0012-155X - p. 1454 - 1480.

    There is a growing interest in localized land registration, in which user rights are acknowledged and recorded through a community-based procedure, as an alternative to centralized titling to promote secure tenure in sub-Saharan Africa. Localized land registration is expected to reduce land disputes, yet it remains unclear how it impacts disputes in practice. This is an urgent question for war-affected settings that experience sensitive land disputes. This article discusses findings from ethnographic fieldwork in Burundi on pilot projects for land certification. It identifies three ways in which certification feeds into land conflicts rather than preventing or resolving them. First, land certification represents a chance for local people to enter a new round of claim making, as those ignored or disenfranchised in earlier rounds see new opportunities. Second, it offers an avenue for institutional competition between different land-governing institutions. Third, certification provides politicians with openings to interfere in tenure relations and to expand their support base. The authors conclude that these problems are not simply a matter of inadequate policy design. Rather, there are crucial political dimensions to land conflicts and land tenure in Burundi, which means that land registration programmes run the risk of inflaming conflictive property relations in rural communities.

    Covid-19 crisis in the Netherlands : “Only together we can control Corona”
    Antonides, Gerrit ; Leeuwen, Eveline van - \ 2020
    Mind & Society (2020). - ISSN 1593-7879 - 7 p.
    Consumer behavior - Covid-19 - Economic measures - Lockdown measures

    The development and management of the Covid-19 outbreak in the Netherlands is described. The “intelligent lockdown” was aimed at minimizing new infections and limiting the number of deaths, while keeping the economy running as much as possible. Changes in consumer behavior, exit strategy, and lessons learned are considered.

    Lure, retain, and catch malaria mosquitoes. How heat and humidity improve odour-baited trap performance
    Cribellier, Antoine ; Spitzen, Jeroen ; Fairbairn, Henry ; De Geer, Cedric Van; Leeuwen, Johan L. Van; Muijres, Florian T. - \ 2020
    Malaria Journal 19 (2020)1. - ISSN 1475-2875

    Background: When seeking a human for a blood meal, mosquitoes use several cues to detect and find their hosts. From this knowledge, counter-flow odour-baited traps have been developed that use a combination of CO2, human-mimicking odour, visual cues and circulating airflow to attract and capture mosquitoes. Initially developed for monitoring, these traps are now also being considered as promising vector control tools. The traps are attractive to host-seeking mosquitoes, but their capture efficiency is low. It has been hypothesized that the lack of short-range host cues, such as heat and increased local humidity, often prevent mosquitoes from getting close enough to get caught; this lack might even trigger avoidance manoeuvres near the capture region. Methods: This study investigated how close-range host cues affect the flight behaviour of Anopheles female malaria mosquitoes around odour-baited traps, and how this affects trap capture performance. For this, a novel counter-flow odour-baited trap was developed, the M-Tego. In addition to the usual CO2 and odour-blend, this trap can provide the short-range host cues, heat and humidity. Systematically adding or removing these two cues tested how this affected the trap capture percentages and flight behaviour. First, capture percentages of the M-Tego with and without short-range host cues to the BG-Suna trap were compared, in both laboratory and semi-field testing. Then, machine-vision techniques were used to track the three-dimensional flight movements of mosquitoes around the M-Tego. Results: With heat and humidity present, the M-Tego captured significantly more mosquitoes as capture percentages almost doubled. Comparing the flight behaviour around the M-Tego with variable close-range host cues showed that when these cues were present, flying mosquitoes were more attracted to the trap and spent more time there. In addition, the M-Tego was found to have a better capture mechanism than the BG-Suna, most likely because it does not elicit previously observed upward avoiding manoeuvres. Conclusions: Results suggest that adding heat and humidity to an odour-baited trap lures more mosquitoes close to the trap and retains them there longer, resulting in higher capture performance. These findings support the development of control tools for fighting mosquito-borne diseases such as malaria.

    Effective physical refining for the mitigation of processing contaminants in palm oil at pilot scale
    Oey, Sergio B. ; Fels-Klerx, H.J. van der; Fogliano, Vincenzo ; Leeuwen, Stefan P.J. van - \ 2020
    Food Research International 138 (2020)A. - ISSN 0963-9969
    3-monochloropropanediol - Elimination methods - Glycidyl esters - Mitigation strategies - Pilot plant refining - Refined edible oils

    This study aimed to develop a mitigation strategy for the formation of 2-monochloropropane-1,3-diol esters (2-MCPDE), 3-monochloropropane-1,2-diol esters (3-MCPDE), and glycidol fatty acid esters (GE) during palm oil refining. Single physical refining was the starting point (the control) for this study. Experimental treatments including a double refining repeating the entire single refining process (T1), double refining with a high-low deodorization temperature (T2), and double deodorization (T3) with similar temperature settings as T2 were performed. Compared with the control experiment, T2 successfully reduced the formation of GE by 87%; in particular, the second degumming and bleaching were crucial for eliminating GE. Both 2- and 3-MCPDE were formed prior to the deodorization process in all treatments. MCPDE concentrations remained stable throughout the refining process and, hence, they require a different mitigation approach as compared to GE. These results provide useful insights which can directly be implemented by the oil industry.

    Goed verpacht, beter beheerd : Een onderzoek naar het borgen van de kwaliteit van de Nederlandse landbouwbodems in pachtafspraken, in opdracht van het Rijksvastgoedbedrijf
    Pleijte, Marcel ; During, Roel ; Silvis, Huib ; Docters van Leeuwen, Herman - \ 2020
    Wageningen : Wageningen Environmental Research (Rapport / Wageningen Environmental Research 3027) - 81
    There are signs that the quality of the soil is deteriorating in large parts of the Dutch farmland. In its capacity as executor of the State’s private law management of agricultural land, the National Real Estate Agency (RVB) wants to investigate how landlords can encourage tenants to use the land in such a way as to safeguard soil quality. On the basis of document and website analysis, literature research, interviews, a workshop and expert judgement the agricultural and legal possibilities to include measures for sustainable soil management in lease agreements, private management agreements and generic regulations have been identified.
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